Algae in the Gulf of Mexico by Houston, Texas, USA
Houston (center left) is the fourth-largest city in the USA and the largest city within the state of Texas. As of the 2007 U.S. Census estimate, the city has a population of 2.2 million within an area of 600 square miles (1,600 km²).
According to the United States Census Bureau, the city has a total area of 601.7 square miles (1,558.4 km²); this comprises 579.4 square miles (1,500.7 km²) of land and 22.3 square miles (57.7 km²) of water.
Most of Houston is located on the gulf coastal plain, and its vegetation is classified as temperate grassland and forest.
Much of the city was built on forested land, marshes, swamp, or prairie, which are all still visible in surrounding areas.
Houston has four major bayous passing through the city. Buffalo Bayou runs through downtown and the Houston Ship Channel, and has three tributaries: White Oak Bayou, Braes Bayou and Sims Bayou.
Houston is connected to the large bay to the southeast by a shipping channel. The bay, which is actually divided into three sections: Trinity Bay (north), East Bay (east) and Galveston Bay (south), is then connected to the Gulf of Mexico.
The bays are brown and green from sediments.